In this psychology experiment:
1. Independent Variable (IV): The independent variable is the factor that the researchers manipulate to observe its effect. In this case, the independent variable is the presence or absence of a full moon. It has two levels: "full moon" and "no full moon."
2. Dependent Variable (DV): The dependent variable is the outcome or response that the researchers measure to assess the effect of the independent variable. In this experiment, the dependent variable is the likelihood of people helping in an emergency situation (stopping and getting out of the car to assist). It's what the researchers are observing and measuring.
3. Experimental Group: The experimental group consists of the participants who are exposed to the experimental condition or treatment, which is the presence of a full moon in this case. In other words, the experimental group includes the 20 males and 20 females who were tested during a full moon.
4. Control Group: The control group, on the other hand, consists of the participants who are not exposed to the experimental condition and serve as a baseline for comparison. In this experiment, the control group includes the 20 males and 20 females who were tested when there was no full moon.
The researchers are comparing the behavior of the experimental group (tested during a full moon) with the control group (tested without a full moon) to determine if there is any significant difference in the likelihood of people helping in an emergency situation based on the presence or absence of a full moon.